HILL: GEOLOGY OF JAMAICA, 170 
the lower part of the Blue Mountain Series, and the Richmond beds 
of Jamaica. Concerning these he says : — 
“The Eocene conglomerates consist of sandstones, clay slates, and stratified 
“onglomerates. The latter predominate decidedly. The constituents of nearly 
ll these beds are almost exclusively of volcanic origin, and are to be attrib- 
“ed to the decomposition and erosion of the porphyritic and syenitic rocks, 
“Specially the former. The porphyritic constituents have in the main imparted 
te red color to this formation. The débris forming these conglomerates is 
ranite, especially syenite and porphyry, also trap, more rarely gneiss; they 
?Té united by a siliceous cement. Alongside of them are found limestone 
Pebbles, whose blue-gray or black color and Hippurite and Nerinea fossils in- 
dicate that they belong to the Jurassic (?) limestone. The texture of the 
Various beds is loose, where no plutonic masses have exerted a hardening in- 
"ence, The sedimentary origin, however, remains recognizable in the lines 
f stratification and in the flat rounded pebbles. The strata, varying in thick- 
ess from a few inches to several fi eet, always appear in regular arrangement. 
t the surface this formation is frequently decomposed into local clays, shining 
hres, kaolin, various siliceous stones, agates, amethysts, and quartz. Such 
Surfaces, either high plateaus or mountain crests, always have a dreary red 
"Ppearance, The clay slates often show a well marked purple color. At the 
ase of this formation occur dark colored clay slates; they seem to extend 
"ck into the epoch of the Jurassic limestone, There they also grow more 
Nch in fossils, and show traces of plants, marine shells, and calcspar veins. Lig- 
lite beds of «mall extent lie between the slates. The sandstones bear impres- 
"ons of leaves and stems. The higher clay slates are light brown or reddish, 
"n form thin beds of friable conglomerates, resting on massive gray sand- 
ès. In the vicinity of eruptive rock the sandstone is hardened, becomes 
"ystalline and transformed into quartz ; elsewhere it is soft and friable. The 
M has been still more changed by heat, having become porphyritic. When 
Posed to the air, it crumbles, the sulphur, iron, and lime being separated and 
mg with the aluminum two differently colored clays, red and gray, used 
Industry.” 
» 
In Cuba the bituminous plant-bearing shales of Esperanza and other 
ps in Santa Clara province and in the vicinity of Havana, previously 
oted by the writer? and others, occupy a position below the great 
hite Limestone Series corresponding to that of the Richmond beds. 
; far as is known the outcrops are not widely developed. 
n Porto Rico, the Virgin Islands, and St. Dartholomew, no attempt 
38 been made to separate this formation from the overlying equivalents 
the Cambridge beds, or to distinguish it from the Bluebeache, but 
Ubtless future study will reveal its presence there. 
* Notes on the Geology of the Island of Cuba, Cambridge, 1895, p. 246. 
